Metal-containing phosphate complexes and method of preparing same



United States Patent "cc 3,215,715 METAL-CONTAHNING PHOSPHATE COMPLEXESAND METHOD OF PREPARING SAME Robert G. Wurstner, Cleveland, Ohio,assignor to The Lubrizol Corporation, Wicklitfe, Ohio, a corporation ofOhio No Drawing. Filed Sept. 22, 1961, Ser. No. 139,845 7 Claims. (Cl.260429.9)

The present invention relates to novel, metal-containing organicphosphate complexes and to a process for their preparation.

In a more specific sense, it relates to the inhibition of corrosion ofmetal surfaces by means of such metal complexes.

The corrosion of metal surfaces is of obvious economic significance inmany industrial applications, and as a consequence the inhibition ofsuch corrosion is a matter of prime consideration. It is particularlysignificant to users of steel and other ferrous alloys. The corrosion ofsuch ferrous metal alloys is largely a matter of rust formation which inturn involves the overall conversion of the free metal to its oxide.

The theory which best explains such oxidation of ferrous metal surfacespostulates the essential presence of both water and oxygen. Even minutetraces of moisture are sufficient, according to this theory, to inducethe dissolution of iron therein and the formation of ferrous hydroxideuntil the water becomes saturated with ferrous ions. The presence ofoxygen causes oxidation of the resulting ferrous hydroxide to ferrichydroxide, which then settles out of solution and is ultimatelyconverted to ferric oxide or rust.

The above sequence of reactions can be prevented, or at least in largemeasure inhibited, by relatively impermeable coatings which have theeffect of excluding either or both moisture and oxygen from contact withthe ferrous metal surface. Such coatings are, of course, subject toabrasion and other forms of physical deformation and to the extent thatthese coatings are penetrated or otherwise destroyed by such influencesthey become ineffective for the desired purpose. It is important thatsuch coatings provide complete protection of all of the ferrous metalsurface. If there is any portion of such a surface which is not soprotected, regardless of how small the unprotected surface may be, thedegree of protection afforded is considerably less than needed. Asatisfactory corrosion-inhibiting coating, then, must have the abilityto resist substantial deformation upon impact, abrasion, etc., so that auniform and complete film is maintained in the face of such adverseinfluences.

Metal salts of acid esters of phosphoric or phosphorothioic acids havebeen investigated by workers engaged in the task of providing protectivecoatings for metal. In US. Patent 2,080,299, for example, Benning et al.propose the treatment of ferrous metals with phosphate acid esters ortheir alkali metal and ammonium salts to prevent rusting. Somewhatsimilarly, Butler and Le Suer (US. Patents 2,861,907 and 2,820,723) findthat salt-esters of various complex phosphorothioic acids are effectivein preventing or retarding the corrosion of metals.

Although such salt-esters of phosphoric and phosphorothioic acids haveprovided means for combatting the corrosion of metals, they have notbeen completely satisfactory because of certain inherent shortcomings.The simple salt-esters of phosphoric acid are readily washed or abradedfrom ametallic surface and thus provide complete protection only undercertain conditions. The saltesters of phosphorothioic acids, on theother hand, have the disadvantage, under certain conditions, ofdeveloping an objectionable odor reminiscent of hydrogen sulfide,

3,215,715 Patented Nov. 2, 1965 particularly when a film of such asalt-ester comes in contact with water or humid atmospheres.

It is accordingly an object of the present invention to provide novelmetal-containing organic phosphate complexes and a process for theirpreparation.

Another object is to provide a means for protecting metal surfaces fromthe ravages of corrosion.

A still further object is to provide a means for substantiallyincreasing the corrosion resistance of phosphated metal surfaces.

These and other objects of the invention are realized by means of aprocess for preparing a metal-containing organic phosphate complex whichcomprises the reaction of (A) a polyvalent metal salt of the acidphosphate esters derived from the reaction of phosphorus pentoxide witha mixture of a monohydric alcohol and from 0.25 to 4.0 equivalents of apolyhydric alcohol, with (B) at least about 0.1 equivalent of an organicepoxide.

Thin films of the aforesaid complexes are effective in inhibiting thecorrosion of metal surfaces, especially phosphated ferrous metalsurfaces.

The acid phosphate esters required for the preparation of startingmaterial (A) are made, as indicated, by the reaction of phosphoruspentoxide with a mixture of a monohydric alcohol and a polyhydricalcohol. The precise nature of this reaction is not entirely clear, butit is known that a mixture of phosphate esters is formed. This mixtureconsists principally of acid phosphate esters, i.e., compounds of thegeneral formula:

where x equals 1 or 2 and R is an organic radical, although some neutraltriesters of the formula (RO) PO may also be formed.

Likewise, the stoichiometry of the reaction is not clear. Based ontheoretical considerations alone, it appears that the following productsare formed:

In actual practice, the reaction does not take place in the quantitativefashion indicated by the above equation. A complex mixture of differentesters results, the relative proportions of which can be altered byvarying the amount of alcohol used from 2 to 6 equivalents per mole of P0 The nature and the stoichiometry of the reaction are complicatedfurther in the present invention by the fact that one of the reactantsis a polyhydric alcohol. Theoretical considerations indicate that apolyhydric alcohol forms cyclic and/or polymeric phosphate esters whenit reacts with phosphorus pentoxide. Indeed, the tenacious character ofthe film formed on metal surfaces by the complexes of this invention isbelieved to be due at least in part to the presence of such cyclicand/or polymeric structures.

In any event, the acid phosphate esters resulting from the reaction ofone mole of phosphorus pentoxide with from about 2 to about 6equivalents of a mixture of monohydric and polyhydric alcohols areuseful in the preparation of starting material (A). The term equivalentas used herein reflects the hydroxyl equivalency of the alcohol. Thus,for example, 1 mole of octyl alcohol is 1 equivalent thereof, 1 mole ofethylene glycol is 2 equivalents thereof, 1 mole of glycerol is 3equivalents thereof, etc.

Less than 2 or more than 6 equivalents of alcohol can be used, ifdesired, the reaction with one mole of phosphorus pentoxide, althoughsuch amounts are not preferred for reasons of economy. When fewer than 2equivalents of alcohol are used, some unreacted phosphorus pentoxide mayremain in the product or precipitate therefrom. On the other hand, whensubstantially more than 6 equivalents of alcohol are used, unreactedalcohol would be present in the product. For the purpose of the presentinvention it is generally preferred to employ from about 3 to aboutequivalents of the alcohol mixture per mole of phosphorus pentoxide.

The monohydric alcohols useful in the preparation of starting material(A) are principally the non-benzenoid alcohols, i.e., the aliphatic andcycloaliphatic alcohols, although in some instances aromatic and/orheterocyclic substituents may be present. Thus, suitable monohydricalcohols are, e.g., propyl, isopropyl, butyl, isobutyl, amyl, hexyl,cyclohexyl, heptyl, methylcyclohexyl, octyl, isooctyl, decyl, lauryl,tridecyl, oleyl, benzyl, beta-phenethyl, alpha-pyridylethyl, etc.,alcohols. Mixtures of such alcohols can also be used if desired.Substituents such as, e.g., chloro, bromo, fluoro, nitro, nitroso,ester, ether, sulfide, keto, etc., which do not prevent the desiredreaction may also be present in the alcohol. In most instances, however,the monohydric alcohol will be an unsubstituted alkanol.

The polyhydric alcohols useful in the preparation of starting material(A) are principally glycols, i.e., dihydric alcohols, althoughtrihydric, tetrahydric, and higher polyhydric alcohols may also be used.In certain instances, they may contain aromatic and/or heterocyclicsubstituents as well as chloro, bromo, fluoro, nitro, nitroso, ether,ester, sulfide, keto, etc., substituents. Thus, suitable polyhydricalcohols are, e.g., ethylene glycol, diethylene glycol, triethyleneglycol, propylene gylcol, dipropylene glycol, 1,3-butanediol, glycerol,glycerol monooleate, mono-phenyl ether of glycerol, mono-benzyl ether ofglycerol, 1,3,5-hexanetriol, pentaerythritol, sorbitol dioctanoate,pentaerythritol dioleate, and the like. In lieu of a single polyhydricalcohol, mixtures of two or more of such alcohols may be employed.

As indicated, starting material (A) is prepared from a mixture ofmonohydric and polyhydric alcohols. The mixture may contain a singlemonohydric and a single polyhydric alcohol, or a plurality of one orboth of such alcohols. For the purpose of this invention, best resultsare achieved when there is present from 0.25 to about 4.0 equivalents ofpolyhydric alcohol per equivalent of monohydric alcohol. The use ofmixtures outside of this range tends to produce either intractableesters, or esters which, when converted to the complex of thisinvention, are deficient in film forming properties. Mixtures ofisooctyl alcohol and dipropylene glycol are very satisfactory and aparticular preference is expressed for a mixture in which thesealcohols, respectively, are present in about equivalent amounts.

The reaction between the alcohol mixture and phosphorus pentoxide isexothermic and can be carried out conveniently at a temperature rangingfrom room temperature or below to a temperature just beneath thedecomposition point of the mixture. Generally, reaction temperatureswithin the range of from about 40 C. to about 200 C. are mostsatisfactory. The reaction time required varies according to thetemperature and to the hydroxyl activity of the alcohols. At the highertemperatures, as little as 5 or 10 minutes may be sufiicient forcomplete reaction. On the other hand, at room temperature 12 or morehours may be required. Generally it is most convenient to heat thealcohol mixture with phosphorus pentoxide for 0.5 to 8 hours at 60-120C. In any event, the reaction is carried out until periodic acid numberdeterminations on the reaction mass indicate that no more acid phosphateesters are being formed.

To facilitate mixing and handling, the reaction may be conducted in thepresence of an inert solvent. Generally such solvent is a petroleumdistillate hydrocarbon, an aromatic hydrocarbon, an ether, or a lowerchlorinated alkane, although mixtures of any such solvents can be used.Typical solvents include, e.g., petroleum aromatic spirits boiling inthe range 250-400 F., benzene, xylene, toluene, mesitylene, ethylenedichloride, diisopropyl ether,

4 etc. In most instances, the solvent is allowed to remain in the acidphosphate esters and ultimately the final metalcontaining organicphosphate complex, where it serves as a vehicle for the convenientapplication of films of the complex to metal surfaces.

The conversion of the acid phosphate esters to the polyvalent metal saltmay be carried out by any of the various known methods for thepreparation of salts of organic acids such as, e.g., reaction of theacid-esters with a polyvalent metal base such as a metal oxide,hydroxide, or carbonate. Other suitable methods include, e.g., reactionof the acid-esters with a finely divided polyvalent metal, or themetathesis of a monovalent metal salt of the acid-esters with a solublesalt of the polyvalent metal such as, e.g., a nitrate, chloride, oracetate thereof.

The polyvalent metal of starting material (A) may be any light or heavypolyvalent metal such as, e.g., zinc, cadmium, lead, iron, cobalt,nickel, barium, calcium, strontium, magnesium, copper, bismuth, tin,chromium, or manganese. A preference is expressed for the polyvalentmetals of Group II of the Periodic Table and of these, zinc isparticularly preferred. A highly effective starting material (A) for thepurpose of the present invention is the zinc salt of the acid phosphateesters formed by the reaction of a mixture of equivalent amounts ofisooctyl alcohol and dipropylene glycol with phosphorus pentoxide.

The formation of the metal-containing organic phosphate complex of thisinvention involves, as indicated, a reaction between starting material(A), the polyvalent metal salt of certain acid phosphate esters, andstarting material (B), the organic epoxide.

The organic epoxides, i.e., compounds containing at linkage where x isZero or a small integer, suitable for the purpose of this inventioninclude the various substituted and unsubstituted alkylene oxidescontaining at least two aliphatic carbon atoms, such as, e.g., ethyleneoxide, 1,2-propylene oxide, 1,3-propylene oxide, 1,2-butylene oxide,pentamethylene oxide, hexamethylene oxide, 1,2-octylene oxide,cyclohexene oxide, methyl cyclohexene oxide, 1,2; 11,12-diepoxydodecane,styrene oxide, alpha-methyl styrene oxide, beta-propiolactone, methylepoxycaprylate, ethyl epoxypalmitate, propyl epoxymyristate, butylepoxystearate, epoxidized soyabean oil, and the like. Of the variousavailable organic epoxides, it is preferred to use those which containat least 12 carbon atoms. Especially preferred are those epoxides whichcontain at least 12 carbon atoms and also a carboxylic ester group inthe molecule. Thus, the commercially available epoxidized carboxylicester, butyl epoxystearate, is very satisfactoryas starting material (B)for the purpose of this invention. If desired, the organic epoxide mayalso contain substituents such as, e.g., chloro, bromo, fluoro, nitro,nitroso, ether, sulfide, keto, etc., in the molecule.

The stoichiometry of the reaction of the polyvalent metal salt of theacid phosphate esters, starting material (A), with the organic epoxide,starting material (B), to form the metal-containing organic phosphatecomplex of this invention is not precisely known. There are indications,however, that the reaction involves about one equivalent each of thepolyvalent metal salt and the organic epoxide (for this reaction, oneequivalent of an epoxide is the same as one mole thereof). This is notto say that complexes made from one equivalent of the polyvalent metalsalt and less than or more than one equivalent of the organic epoxideare unsuited for the purpose of this invention. Complexes prepared usingas little as 0.1 or 0.25 equivalent or as much as 1.5 or 2 or moreequivalents of the organic epoxide per equivalent of polyvalent metalsalt are satisfactory for the purpose of this invention. For reasons ofeconomy and optimum corrosion inhibition, however, it is generallypreferred to use about equivalent amounts of the two starting materials.

The reaction between the organic epoxide and the polyvalent metal saltof the acid phosphate esters is only slightly exothermic, so in order toinsure complete reaction some heat is generally supplied to the reactionmass. The time and temperature for this reaction are not particularlycritical; satisfactory results may be obtained by maintaining the massfor 0.5-6 hours at a temperature within the range of from about 40 C. toabout 150 C. ordinarily, the product is clear and does not require afiltration. In some instances, however, it may be desirable to filterthe product, particularly when the polyvalent metal salt startingmaterial has not been purified.

The following examples are offered to illustrate specific modes ofcarrying out the process of this invention. All parts are by weightunless otherwise indicated.

Example 1 49 parts (0.73 equivalent) of dipropylene glycol, 95 parts(0.73 equivalent) of isooctyl alcohol, and 133 parts of aromaticpetroleum spirits boiling in the range 316349 F. are introduced into areaction vessel. The whole is stirred at room temperature and 60 parts(0.42 mole) of phosphorus pentoxide is introduced portion- Wise over aperiod of about 0.5 hour. The heat of reaction causes the temperature torise to about 80 C. After all of the phosphorus pentoxide has beenadded, the whole is stirred for an additional 0.5 hour at 93 C. Theresulting acid phosphate esters show an acid number of 91 withbromphenol blue :as an indicator.

The mixture of acid phosphate esters is converted to the correspondingzinc salt by reacting it with 34.5 parts of zinc oxide for 2.5 hours at93 C. Thereafter 356 parts (one equivalent per equivalent of zinc salt)of butyl epoxystearate is added to the zinc salt at 88 C. over a periodof about one hour and the whole is stirred for 4 hours at 90 C.Filtration of the mass yields 684 parts of a zinc-containing organicphosphate complex having the following analysis:

Percent phosphorus 3.55 Percent Zinc 3.78 Specific gravity 1.009

Example 2 A cadmium-containing organic phosphate complex is made in themanner set forth in Example 1, except that 54.5 parts of cadmium oxideis used in lieu of the specified amount of zinc oxide.

Example 3 A lead-containing organic phosphate complex is made in themanner set forth in Example 1, except that 95 parts of lead monoxide is.used in lieu of the specified amount of zinc oxide.

Example 4 A barium-containing organic phosphate complex is made in themanner set forth in Example 1, except that 73 parts of barium hydroxideis used in lieu of the specified amount of zinc oxide.

Example 5 A tin-containing organic phosphate complex is made in the,manner set forth in Example 1, except that 57 parts of stannic oxide isused in lieu of the specified amount of zinc oxide.

I Example 6 520 parts (4 equivalents) of isooctyl alcohol, 268 parts -ofdipropylene glycol (4 equivalents), and 1031 parts of toluene solventare introduced into a reaction vessel. The whole is stirred and 243parts (1.71 moles) of phosphorus pentoxide is added portionwise over aperiod of 2 hours. The exothermic character of the reaction causes thetemperature to rise from room temperature to 60 C. To insure completereaction, the whole is stirred for an additional 4 hours at 60 C. Theresulting 50% solution of the acid phosphate esters in toluene shows anacid number of 88 with bromphenol blue as an indicator.

1000 parts of the toluene solution of acid esters is converted to thecorresponding zinc salt by reaction with 83 parts of zinc oxide for 5.5hours at 4045 C. Filtration yields a clear, light-yellow toluenesolution of the zinc salt. 360 parts of this toluene solution(containing 0.34 equivalent of zinc salt) is heated with 25 parts (0.34equivalent) of beta-propiolactone for 5.5 hours at 50- 60 C. to yieldthe desired zinc-containing organic phosphate complex as a 55% solutionin toluene. It has the following analysis:

Percent phosphorus 4.26 Percent zinc 5.05

Example 7 A toluene solution of acid phosphate esters is made in themanner set forth in Example 6.

994 parts of the indicated toluene solution of acid phosphate esters isheated with 76 parts of calcium hydroxide for 5 hours at 45-60 C.Filtration yields the calcium salt of the acid phosphate esters as a 51%solution in toluene.

325 parts (0.52 equivalent) of the toluene solution of the calcium saltis heated with 220 parts (0.52 equivalent) of butyl epoxystearate for 5hours at 5060 C. to prepare the desired calcium-containing organicphosphate complex as a 71% solution in toluene. It has the followinganalysis:

Percent phosphorus 2.34 Percent calcium 1.65

Example 8 A calcium-containing organic phosphate complex is made in themanner set forth in Example 7, except that 38 parts (0.52 equivalent) ofbeta-propiolactone is used in lieu of the butyl epoxystearate. Theproduct has the following analysis:

Percent phosphorus 3.74 Percent calcium 2.75

Example 9 A batch of acid phosphate esters is made in the manner setforth in Example 6, except that the amount of toluene solvent employedis reduced to 443 parts so as to yield a more concentrated (70%)solution of the esters in toluene.

290 parts of this toluene solution is neutralized with a mixture of 28.2parts of zinc oxide and 11.2 parts of calcium hydroxide for 3 hours at5070 C. Filtration of the mass yields a mixed zinc-calcium salt of theacid phosphate esters as a 73% solution in toluene.

116.2 parts of the mixed zinc-calcium salt (0.19 equivalent) and 80.4parts (0.19 equivalent) of 85% butyl epoxystearate are heated for 6hours at 50-60 C. to prepare an 84% solution in toluene of a calcium andzinc-containing organic phosphate complex. It shows the followinganalysis:

Percent phorphous "2.69 Percent calcium 0.22 Percent zinc 3.13

Example 10 A zinc-containing organic phosphate complex is made in themanner set forth in, Example 1, except for the following differences: 58parts of 1,2-propylene oxide is used in lieu of the butyl epoxystearateand the reaction between the Zinc salt of the acid phosphate esters andthe 1,2-propylene oxide is carried out at 30-35 C. rather than 88-90 C.

Example 11 A zinc-containing organic phosphate complex is made in themanner set forth in Example 1, except that 136 parts .73 equivalent) oflauryl alcohol and 39 parts (0.73 equivalent) or diethylene glycol areused in lieu of the specified amounts of isooctyl alcohol anddipropylene glycol.

Example 12 A zinc-containing organic phosphate complex is made in themanner set forth in Example 1, except that 185 parts (1.17 equivalents)of n-decanol-l and 7.9 parts (0.29 equivalent) of pentaerythriotal areused in lieu of the specified amounts of isooctyl alcohol anddipropylene glycol.

The novel, metal-containing organic phosphate complexes of thisinvention are principally useful, as indicated, to provide corrosionprotection for metal surfaces. To accomplish this purpose, the metalsurfaces are provided with a thin film of the complex, which film variesfrom about to about 500 milligrams and preferably from about 100 toabout 400 milligrams per square foot of surface area. Such films may beapplied to the metal surface by any of the ordinary techniques used inthe paint industry such as, e.g., brushing, spraying, dipping, orroller-coating. Depending on the particular mode of applicationselected, the complex may be thinned by means of a solvent such as e.g.,petroleum aromatic spirits, benzene, toluene, and the like to aviscosity best suited for such mode of application. In dippingoperations, for example, 50% solutions of the complexes in toluene oraromatic petroleum spirits have been found to yield a film which, whendry, ranges from about 250 to about 350 milligrams per square foot ofsurface area.

The complexes of this invention are useful inretarding the corrosion ofmany kinds of metals, including iron, steel, ferrous alloys, zinc,aluminum, cadmium, and magnesium. They are particularly effective,however, in extending the life of the so-called phosphated metalsurfaces, i.e., surfaces which have been treated with an aqueousinorganic phosphate solution to form thereon an integral, adherentinorganic phosphate coating. Such coatings are widely used in theautomotive and appliance industries as bases to insure good adhesion ofdecorative top-coats such as paint, enamel, varnish, alkyd resins, epoxyresins, and the like. Generally these inorganic phosphate coatings haveinadequate corrosion resistance, i.e., not much better than that of thebare metal. As a consequence, a phosphated metal surface is verysusceptible to corrosion before the desired decorative top-coat isapplied thereto. The metal fabricating and finishing industries havelong sought a treatment or a material which would protect phosphatedmetal parts, particularly phosphated ferrous metal parts, againstcorrosion to a degree great enough to allow them to be stored outdoors.Thin films of the complexes of the present invention have provided ananswer to this problem by extending the anti-corrosion life ofphosphated ferrous metal parts several hundred-fold.

It is believed unnecessary to lengthen the present specification undulyby a recitation of the many ways in which a metal surface may bephosphated. The literature is replete with patents, e.g., U.S. PatentNumbers 1,206,075; 1,247,668; 1,305,331; 1,485,025; 1,610,362;1,980,518; and 2,001,754; which describe the preparation and use of theaqueous inorganic phosphating solutions. A particularly useful class ofaqueous phosphating solutions for preparing phosphated metal surfaceswhich show excellent response to the metal complexes of this inventionis described in U.S. application Serial No. 373,449, filed August 5,1953, by John A. Henricks, now U.S. Patent 3,090,709. The aqueousphosphating solutions of Henricks contain as essential ingredients zincion, phosphate ion, nitrate ion, and calcium ion. They produce anintegral, tightly-adherent micro-crystalline or amorphous phosphatecoating on metals which is highly desirable as a paint base.

The complexes of this invention are also useful in preventing orretarding the so-called white corrosion of zinc, zinc alloys, andgalvanized (i.e., zinc-coated) steel. They are also effective inincreasing the life of electroplated zinc or electroplated cadmiumsurfaces. They are also useful as corrosion-inhibiting ingredients inmetallic paints such as, e.g., aluminum paints or zincfilled paints.

The utility of the complexes of the present invention in retardingcorrosion is shown by the results obtained in a Salt Fog Corrosion test.

A number of 4-inch x 8-inch panels of clean, solvent degreased, 20-gaugeSAE 1020 cold-rolled steel prepared according to ASTM procedure D 609-52were sprayphosphated for about seconds at 160-165 F. with an aqueousphosphating solution containing 0.15% zinc ion, 0.54% phosphate ion,0.39% calcium ion, and 1.4% nitrate ion. Thereafter, they were sprayedfor about 30 seconds at 70 F. with a 0.01% aqueous solution of chromicacid, water-rinsed, and dried.

Several sets of three panels each were then asembled and/ or furthertreated as shown in Table I:

Table I Panel Set: Description A Clean, solvent-degreased panels.

B n--- Phosphated panels.

C Phosphated panels containing a protective film of 310:10 mg./squarefoot of a commercial zinc phosphorodithioate inhibitor.

D Phosphated panels containing a protective film of 310:10 mg./squarefoot of the complex of Example 1.

1 The commercial inhibitor was obtained as a 40% solution itr Each panelwas dip-coated therein and allowed The complex of Example 1 (an solutionin toluene) was diluted with more toluene to yield a 50% solution. Eachpanel was dip-coated therein and allowed to air-dry.

Each set of panels was then subjected to the Salt Fog Corrosion testdescribed in ASTM procedure B 117-57T. This test employs a chamber inwhich a mist of fog of 5% aqueous sodium chloride is maintained incontact with the panels at i2 F. In the present instance, the panelswere inspected each 0.5 hour of the first six hours for the developmentof rust on the flat areas (edges disregarded) of the panels. Thereafter,inspection was made daily. At the first sign of rust on a flat area, thepanel was removed and the time which had elapsed since the beginning ofthe test was recorded as the Fail Time for that panel.

The results obtained on panel sets A through D are shown in Table II:

1 Panels in this set had an nbiectionable odor after removal from theSalt Fog chamber.

Panels were odor-free,

It will be noted that panel set D (processed according to the presentinvention) offered a significant improve ment in corrosion life overthat observed for panel set C (processed by known methods). In addition,the panels processed according to the present invention did not developan objectionable odor after having been in contact with the Warm, humidatmosphere of the Salt Fog chamber.

What is claimed is:

1. A metal-containing organic phosphate complex prepared by the processwhich comprises the reaction of (A) a polyvalent metal salt selectedfrom the group consisting of the zinc, cadmium, lead, iron, cobalt,nickel, barium, calcium, strontium, magnesium, copper, bismuth, tin,chromium, and manganese salts of the acid phosphate esters derived fromthe reaction of phosphorus pentoxide with a mixture of a monohydricalcohol selected from the group consisting of saturated aliphatic andcycloa-liphatic alcohols containing from about 3 to about 18 carbonatoms, and from 0.25 to 4.0 equivalents of a polyhydric alcohol havingfrom 2 to about 4 hydroxyl groups and containing from about 2 to about41 carbon atoms with (B) at least about 0.1 equivalent of an organicepoxide containing from about 2 to about 57 carbon atoms and selectedfrom the group consisting of epoxy alkanes, epoxy alkyl carboxylicacids, lactones, styrene oxide, and alpha-methyl styrene oxide.

2. The product of claim 1 characterized further in that the monohydricalcohol of (A) is a saturated aliphatic alcohol.

3. The product of claim 1 characterized further in that the polyhydricalcohol of (A) is a glycol.

4. The product of claim 1 characterized further in that the polyvalentmetal salt of (A) is a zinc salt.

5. The product of claim 1 characterized further in that the organicepoxide of (B) is an epoxy alkane containing at least about 12 carbonatoms.

6. The product of claim 5 characterized further in that the organicepoxide of (B) additionally contains a carboxylic ester group.

7. A metal-containing organic phosphate complex prepared by the processwhich comprises the reaction of (A) a zinc salt of the acid phosphateesters derived from the reaction of phosphorus pentoxide with a mixtureof iso-octyl alcohol and dipropylene glycol, with (B) at least 0.1equivalent of butyl epoxystearate.

References Cited by the Examiner UNITED STATES PATENTS 2,080,299 5/37Benning 1486.15 2,346,154 4/44 Denison et al 25238 2,820,723 1/58 LeSuer 11772 2,927,936 3/60 Harvey 260-429 2,930,723 3/60 Drysdale et a1.1486.l5 3,004,996 10/61 Arakelian et al 260429.9 3,010,811 11/61Giammaria 25232.5 3,014,940 12/61 Lynch et a1. 260429 TOBIAS E. LEVOW,Primary Examiner.

1. A METAL-CONTAINING ORGANIC PHOSPHATE COMPLEX PREPARED BY THE PROCESSWHICH COMPRISES THE REACTION OF (A) A POLYVALENT METAL SALT SELECTEDFROM THE GROUP CONSISTING OF THE ZINC, CADMIUM, LEAD, IRON, COBALT,NICKEL, BARIUM, CALCIUM, STRONTIUM, MAGNESIUM, COPPER, BISMUTH, TIN,CHROMIIUM, AND MANGANESE SALTS OF THE ACID JPHOSPHATE ESTERS DERIVEDFROM THE REACTION OF PHOSPHORUS PENTOXIDE WITH A MIXTURE OF A MONOHYDRICALCOHOL SELECTED FROM THE GROUP CONSISTING OF SATURATED ALIPHATIC ANDCYCLOALIPHATIC ALCOHOLS CONTAINING FROM 3 TO ABOUT 18 CARBON ATOMS, ANDFROM 0.25 TO 4.0 EQUIVALENTS OF A POLYHYDRIC ALCOHOL HAVING FROM 2 TO ABOUT 4 HYDROXYL GROUPS AND CONTAINING FROM ABOUT 2 TO ABOUT 41 CARBONATOMS WITH (B) AT LEAST ABOUT 0.1 EQUIVALENT OF AN ORGANIC EPOXIDECONTAINING FROM ABOUT 2 TO ABOUT 57 CARBON ATOMS AND SELECTED FROM THEGROUP CONSISTING OF EPOXY ALKANES, EPOXY ALKYL CARBOXYLIC ACIDS,LACTONES, STYRENE OXIDE, AND ALPHA-METAL STYRENE OXIDE.